Film for still photography is sold as a strip wound into a roll on a spool disposed within a cartridge case. The cartridge case is provided with a film slot from which the film is pulled for exposure and then rewound after the entire roll has been exposed. In some instances, a roll is partially exposed and then rewound and removed from the camera and, at a later time, used again.
The film cartridge is opaque to shield the film strip within the cartridge from light; however, the slot through which the film strip passes is necessarily opened when advancing the film for exposure and when returning the film completely to the cartridge for subsequent development. As long as the cartridge is within the camera, the film is protected from light; however, when the camera is opened, light can enter through the film slot in the cartridge if the film slot has not been closed to light.
U.S. Pat. Nos. 5,200,777 and 5,209,419, assigned to the assignee of the present invention, each disclose pivoted doors which open when film is dispensed through the film slot and which close to seal the film slot after film has been projected from the film slot and is withdrawn back into the cartridge. In this way, when the cartridge is removed from the camera, the film is shielded from light.
While the doors disclosed in the above-identified patents close the film slot, the doors do not provide a shield which substantially completely surrounds the roll of film. Moreover, it may be relatively easy with the prior art arrangements to intentionally or unintentionally open the doors and thus expose the film to light.